Slack-adjuster.



- PATENTED FEB. 10,1903. F. K. HOWARD.

SLACK ADJUSTER.

I APPLICATION FILED MAY 26, 1902.

I0 MODEL.

first rod 5, as best shown in Fig. 2.

UNITED STATES PATENT OFFICE.

FREDERICK K. HOWARD, OF CHICAGO, ILLINOIS.

SLACK-ADJUSTER.

SPECIFICATION forming part of Letters Patent No. 720,147, dated February10, 1903. Application filed May 26, 1902- Serial No. 109,068. (Nomodel.)

To aZZ whom it may concern.-

Be it known that I, FREDERICK K. How- ARD, a citizen of the UnitedStates, residing in the city of Chicago, county of Cook, and State ofIllinois, have invented.a new and useful Improvement in Slack-Adjusters,of which the following is a specification.

My invention relates to slack-ad j usters for railway-brakes; and theobject of my invention is to provide simple and positive acting meansfor automatically taking up the slack resulting from wear on thebrake-shoes and other parts of the mechanism. I attain this object bythe mechanism illustrated in the accompanying drawings, in which- Figurelis a general plan of the mechanism. Figs. 2 and ,3 are enlarged views,partially in section, showing separately the main and auxiliary take-uplinks. Fig. 4 is a detail View of the sliding housing of the auxiliarytake-up. Fig. 5 isa sectional View looking in the direction of thearrows on the line 5 5, Fig. 3.

Similar numerals refer to similar parts throughout the several Views.

1 represents the cylinder, which is supported in any suitable mannerfrom the carbody and furnishes thepower for operating the brakemechanism. The piston 2 is operated by said cylinder and is pivotallyconnected at its outer extremity to the cylinderlever 3. It is usual toemploy a single cylinder for operating the brakes at both ends of thecar, and therefore a second cylinderlever 4 is provided, whichcorresponds to said lever 3, but is pivotally attached at a fixed point,preferably at the rear extremity of the cylinder 1.

The main tie-rods 5 5 are pivotally attached to the levers 3 and 4between the extremities thereof and operate to set up fulcrum-points insaid levers. One of said rods 5 is screwed into or otherwise rigidlyattached to the main take-up link 6. The free extremity of the secondrod 5 has a portion 7 provided with ratchet-teeth adapted to engage thepawls 8 8, pivotallymountedwithinsaidlink. Said link is apertured at itsextremity opposite to the Said pawls and ratchet-teeth are so arrangedthat the ratchet portion 7 is permitted to move l farther into the link6, but is prevented from moving outwardly by the engagement of saidpawls with the ratchet-teeth. In order that said pawls may have a firmbearing to resist the tension in the rods 5, they are so placed as tocontact the shoulders 10, formed at the extremity of said main link. Thesprings 11 are so mounted as to tend to force said pawls to a bearingagainst said link, thereby preventing accidental disengagement from theteeth on the ratchet portion 7. The remaining extremities of the levers3 and 4 are pivotally attachedto the connecting-rods 12.

In the drawings a lever 13 is shown to be pivotally attached at itsextremities to the brake-rods 14 14 and to be attached intermediate ofits extremities to the said connectingrod 12. The precise mode ofattachment to the brake-shoes, however, is not essential, as variousarrangements are well known to those skilled in the art, and it issufficient for an understanding of my invention to state that the brakeparts are so arranged that the movement of the levers 3 and 4, so as todraw the rods 12 12 toward each other, tends to set the brakes. oppositedirection-that is to say, in the direction opposite to the adjacentarrowstends to release the brakes.

The auxiliary tie-rods 15 15 are each pivot-. ally connected to one ofthe levers 3 at at a is apertured to receive the ratchet portion of saidsecond auxiliary tie-rod, as best shown in Fig. 4. The housing 18, whichis slidingly mounted Within said link16, is also apertured to receivesaid ratchet portion 17 of the rod 15. Said housing is by preferencechambered out to receive the pawls l9 and springs 20 acting thereon. Thechief advantage in thus chambering the housing lies in the protectionthereby afforded to the said pawls and springs. The arrangement of thesaid springs and The movement of the rods 12 in the pawls is such thatthe ratchet portion 17 of rod 15 is permitted to enter farther into thehousing, but is prevented from withdrawing therefrom by the said pawls.The springs 20 tend to force their pawls into engagement with the teethof the ratchet portion 17 for preventing accidental releasing of thelatter. The travel of the housing on the link 16 is limited by theshoulders 21, formed atthe extremity of said link, and by the shoulders22, formed intermediate of the extremities ofsaid link. The springs 20are made stiff and strong enough to enable their pawls to engage theratchet portion 17 with sufficient pressure to cause the housing 18 tomaintain its location on said ratchet portion during the free sliding ofsaid housing on the link. When, however, the ratchet-bearing tie-rod 15continues to move inward toward the shoulders 22 after the housing hascome to a stop against said shoulders, the springs permit the pawls 19to release the ratchet portion and allow the same to continue itsmotion. The continued motion of the ratchet-bearing rod after thehousing has contacted the shoulders 22 causes the housing to permanentlymove farther up on said rod, thereby shortening the distance which saidrod can be subsequently withdrawn from the link.

In order to facilitate an understanding of the device, suppose that thebrakes are to be set and that the auxiliary tie-rods 15 and link 16 arenot present. To set the brakes, the piston 2 will move outward and causethe rake-rods 14 to move inwardly in the direction of the arrowsadjacent to the respective parts, the main tie-rods 5 setting up fulcrums at their points of attachment to the levers 3 and 4. Now if theacting length of the rods 5 is too great the movement in the rods 12will be too small and the brake-shoes will not operate properly. Toremedy such defect and adjust the mechanism, the acting or virtuallength of the rods 5 must be shortened, and this adjusting or taking upof the slack is accomplished automatically by the aid of the auxiliarytie-rods 15 and link 16. The oscillation or swinging of the levers 3 4about their fulcrums will cause the rods 15 to approach and recedetoward and from each other. When the mechanism is in proper adjustment,such motion of the rods 15 will cause the housing 18 to slide along thelink 16 without striking either the shoulders 21 or 22 thereon. When,however, the brake system has become slack from any cause, the piston 2when at its extreme outer travel will not have set the brakessufficiently tight-that is to say, will not have caused the rods 15 tohave approached sufficiently near toward each other. In this conditionon the return stroke of the piston while traveling backward into thecylinder to release the brakes the housing 18 will strike against theshoulders 21. Now as the rods 15 cannot recede any farther they set up atemporary fulcrum in each of the levers 3 4 where said rods 15 andlevers 3 4 are connected. The continued motion of the piston causes therods 5 to approach each other, with the result that the ratchet portion7 is engaged by its pawls higher up, thus shortening the virtual oracting length of said rods 5, and thereby taking up slack in the brakesystem. After the slack is thus taken up in the main tie-rods thesubsequent setting of the brakes will cause the auxiliary rods 15 toapproach each other; but as the rods 5 are now shortened the housing 18will strike against the shoulders 22 on the link 16 before the rods 15have completed their mutual approach. This will result in the ratchetportion 17 being pushed farther into the housing and the pawls 19 willengage said ratchet portion 17 higher up than before. The takeupmechanism is therefore again in condition to operate to again shortenthe rods 5 when occasion shall require.

Although I have described my device in its double form, with both lovers3 and 4 movable to set the brakes at the opposite ends of the car, themechanism would operatein substantially the same manner on either onelever if the other lever were fixed. For example, if lever at were fixedor if, which is the same thing, the rods 5 and 15 now connected to saidrods were attached to any fixed points the effect of the mechanism onthe lever 3 would be unchanged.

What I claim as new, and desire to secure by Letters Patent, is-

1. In a slack-adjuster, the combination of a cylinder, levers connectedto said cylinder for operating the brakes, main tie-rods connecting saidlevers between the ends thereof, a ratchet device connecting said maintierods for taking up slack therein, auxiliary tie-rods connected tosaid levers at a portion non-intermediate of the cylinder and maintie-rods, and an auxiliary ratchet device connecting said auxiliarytie-rods for supplementing the action of said main ratchet device, saidauxiliary ratchet device having a definite travel through which it isinoperative.

2. In a slack-adjuster, the combination of a cylinder, levers connectedto said cylinder for operating the brakes, main tie-rods connecting saidlevers between the ends thereof, a ratchet device connecting said maintierods for taking up slack therein, auxiliary tie-rods connected tosaid levers at a portion non-intermediate of the cylinder and maintie-rods, a link rigidly secured to one of said auxiliary tie-rods, anda ratchet device connected to the second of said auxiliary tie-rods,said auxiliary ratchet device being slidingly mounted on said link andhaving a limited amount of travel thereon.

3. In a slack-adjuster, the combination of a cylinder, levers connectedto said cylinder for operating the brakes, main tie-rods con-.

necting said levers between the ends thereof, a ratchet deviceconnecting said main tierods for taking up slack therein, auxiliarytie-rods connected to said levers at a portion non-intermediate of thecylinder and main tie-rods, a link rigidly secured to one of saidauxiliary tie-rods, and a housing slidingly mounted and having adefinite amount of travel on said link, ratchet-teeth on the second ofsaid auxiliary tie-rods, and pawls mounted in said housing for engagingthe ratchet-teeth on said second auxiliary tie-rod.

FREDERICK K. HOWARD.

Witnesses:

J. AvIs BRIGHT, SAD-IE WOLF.

